Rat Lungworm Disease in Hawaii

In November and December 2018, two young dogs in the Honolulu area were diagnosed with Rat Lungworm Disease, caused by Angiostrongylus cantonensis. Both puppies presented with spinal hyperesthesia, hindlimb weakness, and proprioceptive ataxia. One dog had peripheral eosinophilia; all other hematology and serum biochemistry tests were unremarkable. Plain radiographs and computed tomography scans (with/without) contrast were performed but did not reveal a cause for the neurologic signs. Cerebrospinal fluid analysis in both patients revealed eosinophilic pleocytosis and real-time PCR testing for Angiostrongylus cantonensis on CSF was positive in both dogs, confirming a diagnosis of neural angiostrongylisias; PCR testing for other canine neural pathogens was negative.

Both dogs responded rapidly to treatment with corticosteroids and recovered clinically within 2 weeks. Neither dog was observed ingesting a snail or slug, but both dogs had environmental access to them. Dr. Richard Malik (University of Sydney) spoke on this topic in May 2018 and recommends treating with corticosteroids (up to 6 weeks), +/- anthelmintics (if early infection when the larvae are still small and not yet in the CNS), and pain medication or other symptomatic care as needed. He also recommends antibiotics to address the issue of translocated bacteria carried by migrating larvae.

If you have any suspected cases or have questions regarding diagnosing, treating, or preventing rat lungworm infection in dogs or other animals, please call Dr. Jenee Odani (Extension Veterinarian) at 808-956-3847 or email jsodani@hawaii.edu. She is especially interested in conducting post mortem testing on suspected cases.